Training in Zone 4 to Increase Muscular Endurance

The primary goal of the Base 3 period is to improve my muscular endurance while continuing to develop my aerobic efficiency.

The key to improving my muscular endurance over the next 4 weeks will come from increased time riding at my lactate threshold (or zone 4 / FTP). Let’s take a deeper dive into these zone 4 workouts and why they are so important.

The goal of these workouts is to accumulate a total of 20 to 40 minutes cumulative time in zone 4 across each workout.

I’ve scheduled one of these zone 4 / FTP workouts into each week of my 4 week Base 3 block, with the 20 – 40 minute range allowing for plenty of room to increase the total duration at zone 4 across the Base 3 period.

My own tip for maximising the muscular endurance and aerobic benefits of these sessions is to ride an extended amount of time in zone 2 before starting the intervals. I’ll be aiming 90 minutes – 2.5 hours zone 2 before each interval block.

Below is an outline of the interval blocks of each of the workouts, highlighting how they increase throughout my 4 week Base 3 block.

Below is the post workout analysis from my first of these sessions – week 1’s 3 x 8 workout. I rode these intervals on Box Hill, Surrey. Note the total duration of nearly 27 minutes spent in zone 4 and nearly 90 minutes of time at zone 2 before starting the intervals.

Post – workout analysis for 3 x 8 zone 4 workout

Other FTP workouts for increasing muscular endurance

Note: these workouts assume the use of a power meter, although heart rate zones can also be used.

Classic 2 x 20

The classic FTP workout. Tried and tested for many years by professionals and amateurs alike. 20 minutes will feel like a long time and this workout will train you physically and mentally to work for longer durations right on the limit.

After a sufficient warm up, ride for 20 minutes at 91 – 105% of your FTP.

Recover for 10 minutes at upper zone 1 / lower zone 2

Ride another 20 minutes at 91 – 105% of FTP

3 x 15 alternative

An alternative to the classic 2 x 20 session. 3 x 15 minutes gives you an extra 15 minutes of work time compared to the traditional 2 x 20 session. Also as each work block is 5 minutes shorter in duration, you can perform these at the higher end of your zone 4 range.

After sufficient warm up, ride for 15 minutes at 91 – 105% of your FTP. If you can, aim to stay at the upper end of this range.

Recover for 8 minutes in upper zone 1 / lower zone 2

Repeat 3 times for a total of ~45 minutes at the upper end of zone 4 which is a significant amount of training load.

Over / Unders

The goal here is to alternate between riding just above, and just below your FTP. This is a great way to build your body’s tolerance to lactate acid.

After sufficient warm up you will perform 2 x 21 minute blocks of work. Each block consists of the following:

2 minutes at 110% of threshold

1 minute at 90% of threshold

Repeated 7 times = 21 minutes

Thanks for reading, I hope these inspire you to get out there and train these longer zone 4 intervals to improve your muscular endurance.